This invention generally relates to a lighting device for an instrument cluster. More particularly, this invention relates to a lighting device for flood lighting and back lighting an instrument cluster.
Conventional instrument clusters are lit by either lighting from behind a semi-transparent surface or directed light onto the surface desired to be lit. Each method is advantageous for specific applications. A flood light lighting configuration provides light onto a surface that can be controlled as desired. The back light configuration provides an aesthetically desired appearance.
A flood lit configuration will typically include a light guide or housing that blocks light in undesired directions such that light from a light source is directed over a surface of an instrument dial or cluster. The back lit configuration typically includes a light source disposed behind a semi-transparent surface. The light source is typically disposed adjacent the surface and within a housing to prevent light from leaking into undesired areas.
As appreciated, the different lighting configurations require different devices, light sources and housing configurations to manage and direct light as is desired. For these reasons, a flood lit and backlit display is difficult and not cost effective to integrate into a single instrument cluster arrangement. Further, utilization of both a flood lit configuration and a back lit configuration require separate light sources that undesirably increase the cost and complexity of an instrument cluster.
Additionally, conventional lighting devices transmit light through straight sections of light guides that are connected at an angular intersection. The angular intersection or joints generate a bright spot or line that is much brighter than the remainder of the light guide. The over illuminated spot of the light guide is undesirable as it provides a very non-uniform appearance. Accordingly, the transition portion is typically blocked from view, essentially wasting much of the emitted light. Additional or larger light sources are then required to compensate for the wasted light.
Accordingly, it is desirable to develop a light configuration that provides both a back lit and flood lit instrument cluster arrangement, and can be utilized for lighting combined instrument gauge cluster assemblies.